I had the Aquarium screen saver some time back, but that was on a Roku Ultra I purchased from Walmart (model 4660 RW). My Ultra (4660) from Best Buy didn't have it. I figured it was a Walmart thing.
Yeah, I know, the official line is that the suffix means nothing more than the distribution channel. But, there were little things about the "RW" Ultra that indicated otherwise. Like the screen saver.
What device do you have?
Roku Ultra (4660)
Apple TV (5th gen), TiVo, Android TV (MiBox)
Roku boxes from every generation.
Apple TV (2nd, 3rd, 4th gen)